Unroasted, or green, coffee beans have long been “aged” to alter their flavor profile in ways desirable to many coffee consumers. It is theorized that various aging processes in use today were developed to mimic conditions experienced by beans transported via wooden sailing ships. Because the transit time was long, and the holds of the ship permeable, the beans would “weather” in the holds of the ship, altering their flavor in ways which consumers at the destination came to enjoy.
As shipping practices steadily improved, coffee beans no longer aged in the way they previously did. Some of this change is due to the incorporation of different materials in the actual shipping containers and the ships themselves, such as the transition from wooden hulls to steel. Other aspects of this change is due simply to the development of more advanced propulsion systems, dramatically reducing transit times. In response to consumer demand for the flavor profiles represented by the sea-aged coffees, alternative methodolgies were developed to age or weather the beans at origin prior to shipping.
Coffee is also aged for economic reasons. When prices are low, coffee will be put up for aging, with the hope that when the aging is complete, prices will be higher. During years of high prices, little or no coffee may be aged, causing a shortage of aged coffee in the marketplace and in subsequent years.
Methods in use today in places such as India and Indonesia are, essentially, land-based methods that cause the beans to experience conditions similar to what beans transported via wooden sailing ship experienced.
One method of aging consists of placing beans in jute sacks, stacking them in a structure with a roof but otherwise largley open to the weather, e.g., no or minimal walls. The stacks are periodically broken down and rearranged to assure that all sacks are equally exposed to the elements.
Another aging method, especially popular in India for producing the coffee known as “Monsooned Malabar”, involves trucking green coffee to coastal regions (in the case of India, the Malabar Coast) during rainy (Monsoon) season. The coffees are spread on patios in large buildings that have roofs, but large wall openings draped with jute “curtains”. Moist monsoon winds are allowed to wash over the beans, which are frequently raked and monitored to determine rate of moisture uptakes. The jute curtains are used to control the exposure, and in the event exposure is more than desired, the bean are rebagged temporaily, then returned to the monsooning patios until the desired finish conditions are achieved.
Aging coffees via these methods can require many months or even years of processing time. During the process, the coffees are susceptible to spoilage via mold, mildew or damage from pests. Because of the risks inherent in these methods, it is not unusual for less desirable raw inputs to be used.
Both methods result in a similar final product. The aged beans, when roasted, have flavors of earth and minerals, and often vegetal character. Most distinctively, they tend to have a “mellow” cup character that is noteworthy for its lack of acidity-aged coffees can be described as “flat”.
Recently, a few coffee roasters have taken note of aging methodologies used in the wine and spirits industry, specifically cask aging, whereby the product of interest is placed in a wooden barrel for a time to impart unique flavor characteristics. In many cases, the desired effect is a “woody” flavor profile. In some cases, used, charred spirit barrels (e.g., whiskey) are used to impart deeper, smokier flavor. These methods, like the older ones before them, take a long time (many months to years) and result in coffees with low acidity in the cup.
The methods described have several shortcomings. In the case of coffees exposed to weather, the chance of spoilage or other loss is a significant drawback. Naturally weathered coffees are also subject to variability in the character of the finished batches, a disadvantage in a market where consumers desire predictable flavor profiles. In all cases, the length of time required to age the coffees is undesirable. Finally, and perhaps most importantly, the “flat” cup profile is an undesirable, and until now, unavoidable characteristic of aged coffees. This fact is evidenced by the methodologies used to grade coffees for establishing their market value. Acidity is a desirable characteristic that warrants its own category in every major scoring methodology, e.g., the Specialty Coffee Association of America (SCAA) Cupping Protocol. Coffees with higher acidity are awarded more points than coffees with low acidity, and accordingly suffer in terms of market value. Traditional processes also lack relationships to brands popular with consumers, and the ability to market the resulting coffee in connection with a brand.